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Scaynes Hill Village

I first got really interested in energy saving in the home about 6 years ago.  It was around then I became aware that our quaint 4-bedroom Victorian cottage was actually rather like the motoring equivalent of a gas guzzling 4x4 and that the price of gas and electricity was starting to rise rapidly after a long period of relatively stability.

Confessions of an Energy miser..... or how we halved home energy use in 6 years

24 Nov 2012 Posted by Graeme de Lande Long

The loft is normally the next culprit in the heat loss battle, which is why you can generally get grants for loft as well as cavity wall insulation.  This makes wall and loft insulation some of the most efficient and cost effective ways to save a lot of energy.  Due to an earlier loft conversion (with good insulation) there was potentially only a small area of loft remaining and improving the insulation would have saved only about 1% of our energy use while being awkward to do, so this was also consigned to the low priority list.

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However, the model did show a lot of heat was being lost through the ground floor into the cellar below.  By insulating the floor (or rather the cellar ceiling) with 100mm thick Rockwool batts (sheets) the model indicated we could save up to a further 5%.  At the same time as doing this we also replaced the lagging to the hot water pipework in the cellar, carried out a programme of draught-proofing windows and doors as well as using a chimney balloon to restrict ventilation up the chimney and added heat reflectors behind radiators mounted on external walls.  In an old house draught proofing is probably the easiest and most cost effective way of saving energy. Finally we replaced some remaining single glazed windows with double glazing.

After last winter we were able to see that these measures had further reduced our energy consumption by an additional 20% making a total reduction of 53% over about 6 years. The Chart to the right shows the year by year savings and the Table above gives a rough breakdown of the savings and the cost return period for each measure.  This will vary depending on your particular house. Despite the price of gas and electricity going up by  50% to 100% over this period we have still managed to reduce our energy bills by about 20%.   We would like to have been able to add a PV panel to do even better, since the Government has set the Feed-in Tariffs it pays to give about 5% return on the initial investment.  However, the appropriate roof space is already taken by the thermal panel, so sadly we are not able to take advantage of this scheme.

In the process of achieving these savings I have done a fair bit of research and learnt a lot about what works and what doesn't.  I would be most happy to share this experience and give what advice I can to anyone who wants to try and improve the energy efficiency of their house.  I can be contacted by e-mail at delandelong@onetel.com or by phone (831364).

As anyone who is familiar with spreadsheets knows they are great for doing 'what-if' scenarios by changing assumptions.  The model was very helpful in showing me where most of the heat losses were occurring so enabling me to target my effort to where it would do most good. In an un-insulated house normally about a third of the heat loss from the house is through the walls, which was confirmed by the model.  However, without a cavity to fill with insulation the cost and potential disruption of additional insulation either internally or externally made this a lower priority - maybe something to be investigated further in future. Nevertheless you don't need a model to tell you the most obvious saving, which costs absolutely nothing, is to reduce the room thermostat setting for the central heating. So we did this gradually and started to wear rather warmer clothing around the house, saving probably about another 15% of our total energy consumption.

After returning from living abroad for about a year (2008-9) when our children were occupying the house we were able to see the results of our work since the annual energy consumption had dropped by about a third, nearly half of which could be attributed to the more efficient boiler. With this encouragement we felt further motivated by the "10-10 Challenge" which was to use 10% less energy in 2010 than in the previous year.  I started to look more seriously at the issues around home energy efficiency and with the help of others and some online research I was able to establish a spreadsheet model of the heat losses from the house based on the Government approved procedure for the assessment of house energy efficiency ratings.  I became quite geeky about thermal coefficients, 'U-values', degree-days  and other such esoteric matters regarding heat loss, home insulation and energy efficiency.

Shortly afterwards we decided that it was time to replace our 20+ year old central heating gas boiler with a more efficient condensing model and at the same time added TRVs (Thermostatic Radiator Valves) to those radiators in the house which did not already have them.  The age of the house meant that most of the external walls are solid brickwork with no cavity to fill.  However, this wasn't the case for an extension added by previous owners in the 1970s, so we took advantage of a government grant scheme to have cavity wall insulation installed at a very modest cost.  Other measures we took at that time involved a long overdue kitchen replacement so we tried to ensure that new appliances (fridge, freezer, dishwasher etc) were energy efficient and we also started using energy efficient light bulbs to replace conventional ones as they failed.